1. Field of the Invention
The present invention relates to a transmission electron microscope and a method of observing a sample under a transmission electron microscope.
When a sample is observed under a transmission electron microscope, aberrations such as rotation aberrations or distorted aberrations (distortion) appear in magnified images due to the limits of lens characteristics. In an observation at a low magnification, the influence of aberrations is particularly noticeable. However, observations of wide fields at a very low magnification with a transmission electron microscope are demanded in application fields particularly such as pathological diagnosis.
In response to these needs, conventionally lens constitutions are altered, or a viewing coverage recorded on a recording medium, for example a range recorded to a film is changed so that lens aberrations may not be included within a field of view as few as possible.
On the other hand, in recent transmission electron microscopes, CCD cameras are used instead of films as recording media of images. However, it is impossible for general-purpose CCD cameras to obtain digital images with a resolution equivalent to that of films due to the limitation of pixel sizes. Thus, techniques of creating montage photos are used to improve the resolution of images.
The specification of Japanese Unexamined Patent Application Publication No. Hei 7-130319 (corresponding to U.S. Pat. No. 5,523,567) discloses that a sample is divided into a plurality of sections and that an image data per section obtained by electron beam scanning is recorded in a frame memory to display a low magnification image.